The head of Kyrgyzstan's new interim government yesterday revealed that her country was broke and said that the former president who was overthrown in a street-led revolution this week had left only $80m in the budget.

In an interview with the Guardian, Roza Otunbayeva appealed for urgent international aid so that the impoverished Central Asian nation could meet its immediate bills. "Tomorrow we should pay pensions. This is a really serious problem," she said.

Otunbayeva said that the ousted president Kurmanbek Bakiyev had plundered the economy, installing his sons in key government positions and flogging off strategic state industries for a fraction of their true value.

She said the country's leading telecoms firm had been sold to an offshore company in the Canary Islands, belonging to a friend of the president's son Maxim. "We had an absolutely scandalous situation where Kyrgyzstan had become a family-run regime," she said.

Otunbayeva, a former foreign minister, said popular anger against the president and his relatives exploded after he imposed new tariffs on 1 January on electricity and hot water. She said the revolt started in the freezing mountain town of Talas in early March, then spread across the country.

On Wednesday elite police shot dead at least 76 people and injured 1,450, when protesters tried to seize the main government building in the capital Bishkek. Bakiyev– who fled to Jalal-Abad near the Tajik border – now had to answer for his crimes, she said. "We guarantee him only his physical safety," she made clear, ruling out any negotiations.

Otunbayeva, who served in London as Kyrgyzstan's ambassador between 1997-2002, said her new opposition-led government would allow the US to continue using the Manas airbase, near Bishkek, a vital supply post for the US military moving in and out of nearby Afghanistan. "We will respect our existing commitments," she said, adding she hadn't seen the contract.

The base is a source of tension with Russia, which regards Central Asia as its backyard, and would like the Americans to leave. Bakiyev fell out with the Kremlin last year after promising to evict the US from Manas in return for large loans, only to renege on the deal when the Obama administration offered to substantially up the rent.

Otunbayeva, however, hinted that the new government sees Russia as its most important strategic partner. She said she had sent her deputy Almazbek Atambayev to Moscow to hold talks with Vladimir Putin, and to discuss economic aid. "I had a talk with Mr Putin. He was very keen to learn what was going on in Kyrgyzstan and whether we had control in the south," she said.

She denied that the Russians had instigated Wednesday's uprising. Putin has quickly recognised the new regime. "I met with the Russian ambassador two or three weeks before the revolution but I also met with the US, EU and Chinese ambassadors too," she said.

The US also dismissed rumours of Russian plotting. Michael McFaul, Obama's senior director for Russian affairs, said: "The people that are allegedly running Kyrgyzstan ... these are all people we've had contact with for many years," McFaul said. "This is not some anti-American coup, that we know for sure. And this is not some sponsored-by-the-Russians coup, there's just no evidence of that."

The interim government was taking advice from the Organisation for Security and Cooperation in Europe over the drafting of a new constitution, she said. It plans to hold elections in six months, and will probably replace the old presidential system with an European-style parliamentary democracy, she added.

Otunbayeva served for a year as Bakiyev's foreign minister before quitting in disgust. The events of the last week had seen history repeat itself, she said: "We've had a very sad lesson in democracy learning. If people are not respected, if they are totally depressed, then one day they will explode and rise up. Unfortunately I have seen this for a second time with my own eyes."

Yesterday mourners gathered in central Bishkek and at funerals around the city for the victims, many of them enraged by the actions of the security forces, who had fought running battles with armed protesters.